Iraqi Bulletin of Geology and Mining

The Cenomanian-Early Turonian Mishrif Formation, which has been studied in selected Oilfields of Tuba Well (TU-5, TU-24, TU-40) and Zubair Well (ZB-41, ZB-42, and ZB-46), which are located in the Mesopotamian basin, southern Iraq, and considered major carbonate reservoir in Iraq and the Arabian Gulf. Seven microfacies types are identified showing that Mishrif formation deposited in five sedimentary facies: 1. Basin Facies Associations; 2. Deep Marine Facies Associations: Bioclast pelagic foram mudstone-wackestone; 3. Shallow Open Marine Facies Associations: Foraminiferal bioclastic wackestone-packstones; 4. Rudisted Reef Facies Associations; 5. Shoal Facies Associations: Peloidal packstone-grainstone; 6.aBack-shoal Facies Association: a. Foraminiferal-bioclastic wackestone-packstone, b. Rudisted-foraminiferal wackestone-packstone; 7. Lagoon Facies Associations: a. Fossiliferous mudstone-wackestone, b. Bioclast foraminiferal wackestone, c. Benthic foraminiferal wackestone.

Fracture analysis was carried out through three adjacent traverses. The study area is considered a part of the Arabian Plate and geologically falls within the boundary between the Low Folded Zone and the High Folded Zone of the Western Zagros Fold-Thrust Belt in the Iraqi Kurdistan Region. Five formations are cropped out in this anticline, extending from the Late Oligocene up to the Late Miocene – Pliocene. Those formations are (Anah, Jeribe, Fatha, Injana, and Mukdadiya). In addition, identify an Oligocene unit the Kirkuk Group, represented by the (Anah Fn.) that no other studies have previously referred to, in addition, to observing the Jeribe Formation along Tilyan Gorge. About 350 fracture planes were measured for the study and classified into sets and systems concerning their relations to the three mutually perpendicular geometrical axes (tectonic axes). Tension sets are (ac), which are formed by extension along the fold axis accompanying direct compression perpendicular to the fold trend, whereas the (bc) set is supposed to be the product of relaxation that motivated the primary compressional stress. The shear systems are each of hk0, h0l, and 0kl developed successively during direct compression and subsequent relaxation episodes of each tectonic stress. The results of the paleostress analyses showed that there is a general coincidence in the direction of the major stress axis (σ1) and the minor stress axis (σ3), which were derived from the joints (fracture planes). Joints are presented as sets and systems. The analysis of joint attitudes revealed that the joints might be due to the influence of the main horizontal compression paleostress in the direction NE – SW that is responsible for folding, or they might be caused by the stretching of the outer arc for the folded layers. According to field observations and paleostress studies, the region experienced four stress stages. The first is a main compressive tectonic phase in the NE – SW direction. The second phase is the second compressive tectonic stress in the direction NW – SE. The third was a NE – SW extension tectonic phase that originated during the final uplift stage of folding and it is representative of the major fold trend. The fourth is the NW – SE extension face considered as the extension stress connected to the principal NE – SW compressive stress.

During the period of 2020 to May 2022, the Iraqi Kurdistan region experienced several small to moderate size earthquakes. The seismic waveform data of these earthquakes were collected from regional and local broadband seismic stations. Waveform data was analyzed for seventy earthquakes to determine their source parameters, which may contribute to the active tectonics in those areas. Moment tensor inversion is estimated for the detected local earthquakes by analysis of observed seismic waveforms in different selected areas. The waveform inversion determines the seismic moment, depth, and kind of rupturing fault at the source. A grid search is employed as part of the inversion procedure across the strike, dip, and rake angles for each depth between 0.5 and 40 Km in increments of 1 Km. Waveform modeling is used to correlate the observed and created waveforms by applying bandpass filters and a suitable velocity model for Green's function using computer programs in seismology and the ISOLA code" Isolated asperities" for multiple-point source modeling. The results show that the earthquakes with M ≥ 4 have a focal depth ranging between 7 and 20 Km. Furthermore, the regional stresses were identified and the mechanism for the optimum fit was determined. The source mechanisms in the study area are most likely a combination of strike-slip, oblique-slip, and thrust.

The present effort is expected to consider the groundwater quality of the Erbil Central Basin. In this study, we compared the physiochemical properties and distribution of major cations and anions in groundwater to evaluate the quality assessment as a special usage (drinking and irrigation) and identify the sources and types of water quality variation and pollution. The mean richness of major cations are Ca2+ > Mg2+ > Na+ > K+, whereas the major anions are HCO3- > SO42- > NO3- > Cl-. The quality of water was evaluated using SAR, sodium (%), PI, TH, MH, PS, and WQI. When the chemical and physical characteristics were compared to Iraqi and public health standards (IQS) for drinking water, it was discovered that the majority of the wells' groundwater during both periods was within the acceptable range, and suitable for all human drinking and domestic purposes except for three wells exceed the maximum permissible limit of NO3-, which are Newroz, Rizgari, and Birayaty, while HCO3ˉ is showed a maximum in Newroz, and in Rizgari well the total hardness (TH) doesn’t lie within recommended standards. The Ca and Mg- Bicarbonate type was the predominant form for the groundwater classified for both seasons, with only one well (Zanko) being Ca- Chloride type for the dry season. The majority of ionic species originated from alkaline earth metals that originate from interactions between weak acidic anions in groundwater and soil or rock. All samples were suitable for drinking water according to the WQI, only the Zanko well had poor water during the dry season.

The objective of this research is to evaluate the suitability of some clay deposits from the Gercus Formation (Middle Eocene) in the Dokan area, Northeastern Iraq for brick manufacturing. Physical properties of the raw material including grain size analysis and Atterberg limits showed that composed mostly of sand and silt with a minor proportion of clay and classified as muddy sand. According to the plasticity chart, the studied sample plotted on the field of silt and organic clay with low plasticity. The geochemical analysis by X-ray fluorescence revealed that composed of a low percentage of silica and alumina and a high percentage of calcium oxide and magnesium oxide. The mineralogical analysis by X-ray diffraction showed that the studied samples were composed of non-clay minerals (dolomite, quartz, hematite, albite, anatase, and orthoclase) and clay mineral (montmorillonite, kaolinite, and illite). Twelve ceramic briquettes were prepared from the clay sample by semi-dry pressing method and pressed by 200 kg/cm² pressure with 14 – 15 % moisture content and fired at 880, 900, and 920 °C for evaluation tests of linear firing shrinkage, apparent porosity, water absorption, bulk density, efflorescence, and compressive strength. Results of physical and mechanical properties of the studied ceramic briquettes compared with the specification of Iraqi standard (1993) for clay brick manufacture, according to this specification the studied sample was not suitable for brick manufacturing due to a high percentage of water absorption and low compressive strength.

A succession of slightly siliceous limestone of the Kometan Formation is studied geochemically and strati graphically. The studied area is located on the SW limb of the Azmir anticline at the northeastern of Sulaimaniyah city. The studied section is situated at longitudes 45°38'310"E and latitudes 35°36'129''N inside the Folded Zone, Kurdistan Region, northeastern Iraq. The exposed section is sampled for lab studies, and inspected by eyes and hand lenses in the field. In this study, petrographic and geochemical analyses of 17 limestone samples were carried out. This study aims to investigate the major oxides of the limestone samples, using the X-Ray Fluorescence (XRF), for preliminary assessment for possible cement production. A petrographic study was also carried out, in order. Depending on the petrographic study, three major microfacies were recognized: lime mudstone microfacies, lime wackestone microfacies, and lime packstone microfacies, which subdivided into four submicrofacies are planktonic foraminifera lime mudstone submicrofacies, planktonic foraminifera lime wackestone submicrofacies, and planktonic foraminifera lime packstone submicrofacies and heterohelix lime packstone submicrofacies. The geochemical analysis shows that a range of variations in constituents: LOI (35.90% to 42,72%), SiO2 (3.77% to 14.66%), CaO (42.59% to 49.95%), Al2O3 (0.44% to 2.22%), Fe2O3 (0.02% to 0.78%) and MgO (1.50% to 2.26%); K2O and Na2O are present in traces. The high CaO (49.95%) indicates that calcite is the primary carbonate mineral. Due to mineralogical considerations, CaO with LOI shows a positive correlation, whereas CaO with SiO2 shows a negative correlation. The low MgO contents in calcitic limestone and calcitic limestone with chert nodules recommend a lack of dolomitization process. The silica modulus and lime saturation factor from geochemical data indicated that the siliceous limestone samples from the Kometan Formation and Azmir Anticline can be used in the cement-making process provided they are processed for silica removal treatment to reduce its percentage to less than 8%, as required level, where the CaO can be automatically enriched. Depending on field observation, petrography, and geochemistry analysis, we conclude that the source of the chert or silica minerals is diagenetic processes and depositional environment origin.

Fifteen samples of brown detrital limestone beds within the Sarmord Formation from the Imbricated Zone (Qaiwan and Barzinjah sections) and High Folded Zone (Zewe section), Kurdistan region, NE-Iraq were analyzed. The analysis includes the major oxides, trace elements, and rare earth elements (REEs) to find out their provenance, tectonic setting, and depositional environment. These beds are mainly composed of detrital limestone in which calcite and traces of quartz are confirmed by XRD and the microscopic study. Al2O3/TiO2, La/Sc, La/Co, Th/Sc, Cr/Th and Th/Cr ratios and {(TiO2 + V2O3) - (MgO/ (MgO + Al2O3)}, (TiO2 - Ni), (La/Th - Hf), (La/Sc - Co/Th) diagrams reveal sourcing from the mixed carbonate platform and felsic rocks. The ratios of major, trace, and REE with PAAS values fall within the range of felsic rocks, which agree with Cretaceous western Iraq (present Western Desert) as a source of these beds. The (Rb – Sr – Ba) ternary diagram and (Sr/Ba-Sr/Rb) diagram display the distribution of the samples between the continental margin and inland field. Tectonically, these detrital limestones are transported from the erosion of the interior of the Arabian platform into deep marine and interbedded with the green marl. The V/Cr, U/Th, Ni/Co, and Sr/Ca ratios and diagram of Al2O3-V indicate deposition under shallow marine oxic to the dysoxic environment and transported to the deep marine. The paleoclimate index C-value, Sr/Cu ratio, and SiO2 - (Al2O3 + K2O + Na2O) diagram indicates hot arid conditions. Paleosalinity ratios Rb/K and Sr/Ba imply brackish to marine water conditions.

This paper intends to provide background information on the chemically investigated raw materials used in the cement industry at the Gasin Cement Factory. Since it was found that the average carbonate ratio of CaCO3 is 89.84 percent by weight ratio, the sulfide is less than 1 percent by weight ratio, and the magnesium carbonate is less than 3 percent, the raw materials entering the factory, including limestone, clay, iron, sand, and gypsum, were examined. Magnesium carbonate was less than or equal to 3 percent, in the iron with sand mixture, and the overall mixture carbonates were less than or equal to 76.24 percent. The findings of the analysis for silica oxides in the sand were greater than 82 percent. For sulfide oxide less than 1%, as well as for iron, the average value of ferric oxide that was examined in a laboratory was 35.51percent, from local iron ore, and an average reached 50.66% from Iranian iron ore, the percentage of alumina oxide that was tested in a laboratory was 9.37 percent and 3.40 percent from Local iron and Iranian iron respectively, silica oxide is more than 8.3 percent. As well as gypsum analysis, it was discovered that the average percentage of sulfur dioxide is higher than 40.97%. We identified the locations of the models that were evaluated and analyzed, as well as their storage locations.

This paper demonstrates the influence of slope geometry and scale of the joint networks on the stability and failure mechanisms in discontinued rock masses. These analyses are based on the finite element method (FEM) to calculate the factor of safety (FOS) and to simulate the explicit discontinuity deformations for different scales of rock masses. The study was carried out through examples of regular jointed models having different slope heights and irregular jointed dry rock slopes. Joints usually decrease the strength of the slopes and suggestively increase slope stability problems. The result shows that the slope stability decreases with increased block size and shape and that the irregular columnar joints are more unfavorable to the slope stability than the regular joints. Furthermore, with dropping the factor of safety and randomly distributed joints the rock failure mechanism appears to shift from structurally controlled for the 50 m slopes towards a step-like failure path for the 100 m and 200 m slopes.